The β-cell mass of the islets of Langerhans in the pancreas is a key factor in determining how much insulin can be secreted for the normal control of blood glucose levels. Noninvasive methods to determine the functional capacity of β-cells are needed to provide, e.g., a biomarker in monitoring the efficacy of novel therapies of, e.g., diabetes, islet regeneration, and pancreas transplantation.
Vesicular monoamine transporter 2 (VMAT2) receptors are expressed by β-cells. Using analogs of tetrabenazine labeled with, e.g., 11C or 18F (such as [11C]dihydrotetrabenazine [DTBZ]) that bind specifically to VMAT2, it has recently been shown that PET has the potential to image binding of the radioligand to VMAT2 in the pancreas. However, there are no known diagnostic PET data analysis tools that are appropriate to quantify the capacity of functioning β-cells in the pancreas.
Thus, there is a need for methods for, e.g., determining the capacity of pancreatic β-cells using PET.